General description The Sollbry 3Pcs Step Drill Bit set includes three sizes: 4mm-12mm, 4mm-20mm, and 4mm-32mm. These high-speed steel (HSS) drill bits are designed for efficient drilling in various materials including steel, brass, wood, and plastic. Technical specifications Material: High-speed steel (HSS) Sizes: 4mm-12mm, 4mm-20mm, 4mm-32mm Thickness capacity: Up to 3mm Usage The Sollbry step drill bits are ideal for processing thin materials such as: Iron plates Aluminum Insulation boards PVC boards Wood boards